Fabrication and design of metal oxide substrates for perovskite solar cells

In this thesis, the production, characterization, and cell applications of optimized indium tin oxide (ITO) and fluorine-doped tin oxide (FTO) substrates for use in planar perovskite solar cells (PSCs) were carried out. The aim of this study is to produce metal oxide substrates that offer superior optoelectronic properties compared to commercial substrates, thereby improving the performance of perovskite cells. ITO and FTO substrates were produced using the magnetron sputtering method with RF and DC power supplies at different power levels (optimum values of 320 W and 137 W, respectively) under an ideal system pressure of ~5 x 10⁻³ Torr. This strategy was chosen due to plasma instability and fluctuations at low pressures. Production was conducted at room temperature for ITO and at 150 °C for FTO. During FTO production, a small amount of oxygen was introduced to correct potential oxygen deficiencies in the structure. The electrical resistances of the produced ITO and FTO-coated glass were measured, followed by annealing at various temperatures in an atmospheric environment. Characterization results revealed that ITO substrates, in particular, exhibit promising properties for solar cell applications. The ITO and FTO substrates were used as electrodes in cells with the electrode/c-TiO₂/perovskite/spiro-OMeTAD/Au architecture, and their photovoltaic performance was compared to commercial ITO (Sigma-Aldrich, Kintec) and FTO (Sigma-Aldrich) substrates. Results showed that the ITO films developed within this project demonstrated enhanced optical and electrical properties compared to commercial ITO, and higher photovoltaic efficiency was achieved. According to current density-voltage (J-V) characteristics, the champion cell using commercial ITO achieved an efficiency of 19.9%, while the cell using ITO developed in this thesis reached an efficiency of 20.2%. In conclusion, this thesis demonstrates that optimized ITO substrates have significant potential to enhance the efficiency of perovskite cells and may find broader applications in optoelectronic device technology in the future.